1. Field of the Invention
The present invention relates to an insulation system for a conduit or container having a surface temperature below the dew point of the ambient air and comprising an inner layer, a heat-insulating layer located on the exterior side of the inner layer and an outer layer located on the exterior side of the heat-insulating layer. In particular the invention relates to an insulating system for insulating cold pipes and conduits and containers for the transportation or storage of cooling media.
2. The Prior Art
It is well-known to insulate hot water pipes by mounting thereon a tubular insulation comprising axially slotted tubular insulating elements. Such tubular insulations are readily mounted and they are effective for preventing loss of heat from the heating pipes.
If such tubular insulations are used in connection with cold pipes, moisture inevitably penetrates through the insulation by diffusion and gets into contact with the surface of the cold pipe. If the surface temperature is below the dew point of the ambient air, condensation of water vapour on the cold pipe will occur and thereby the insulation material becomes moist and-loses its insulating capacity. Furthermore, the insulating material may decompose and the cold pipe may corrode.
The removal of moisture from the insulating material normally takes place very slowly as conventional insulation materials have little capillary effect.
The result is that the tubular insulation remains moist.
The exterior surface of such tubular insulations are usually covered by a layer of a vapour-proof material, such as an aluminium foil or a plastic film, in order to slow down the moistening of the insulating material.
However, experience shows that unavoidable flaws in the vapour-proof foil or film result in severe moistening of the insulating material over the years, and unfortunately in this situation the vapour-proof layer will prevent drying of the heat-insulating layer by capillary suction.
Up to now the only solution to this problem has been periodic replacement of the wet insulation.
SE-C-123644 discloses an insulating system comprising an inner sealing layer, e.g. consisting of asphalt, a heat-insulating layer composed of adjacent elements of trapezoidal cross-section and located on the exterior side of the inner layer and an outer sealing layer, e.g. consisting of asphalt.
It is the object of the invention to provide an insulation system for conduits and containers of the above-mentioned type which instead of preventing water vapours from entering the insulation system, ensures that moisture present therein is continuously removed therefrom.